Are you currently on any prescription medications? They can interfere with breast feeding/pumping. I'm wondering, since you say you have to dump a lot of milk. I was on one medication for high blood pressure when I delivered my daughter ten years ago; I either didn't/couldn't produce milk, and/or the prescription drug made it worse. I tried to pump, but was unsuccessful. I mean, really, I pumped for four weeks, almost nonstop, and could barely produce anything. I ate well and drank lots and lots of water.
My daughter was born early and unable to latch. I kept trying to get my daughter to latch, but she absolutely refused. I tried to give her as much of my milk as possible; she eventually completely refused any breast milk, including if it was mixed with formula (I still wonder if she could tell/taste the prescription med in there). Talking with La Leche/having a consultation didn't help.
To this day, I still lament that I had to formula feed and couldn't breast feed. But it is what it is. Other posters are right; stressing or worrying won't help.
Sometimes, breast feeding just doesn't work. I have to content myself with knowing that I gave my daughter as much of my milk/colostum as possible. When you're sick yourself, the last thing you want to be angsting over is breast feeding. Do what you can, but please, don't beat yourself up over it if you're unable to breast feed her as much as your other children. You have done your best; take care of yourself as well.
She will survive. My grandmother couldn't produce milk, and she raised four children. This was back when there was no infant formula. She fed them watered down evaporated milk. ::shrug:: My dad and my aunt and uncles all lived, thrived, and haven't had any health problems.
Do what you have to for your baby, but please, take care of your own health concerns as well. A big part of the problem for me were my own health concerns/problems after my daughter was born. You need to take care of yourself, so that you can take care of your newborn and your other children as well.
If it ends up that your baby can't have breast milk--it's okay. She'll be fine. If you're concerned about using infant formula, see if you can find someone to buy raw goat milk from. If I could do it all over again, that's what I would feed my daughter.